NEW YORK (AP) Juan Martin del Potro's magical month ended as it began - with the big Argentine crying on the court.
This time, he wiped away tears with the match still going. Stan Wawrinka was about to serve out a four-set victory to usher an exhausted del Potro out of the U.S. Open, and the hardy faithful who stuck around past 1 a.m. wanted to serenade their beloved 2009 champ one more time.
''Ole, ole, ole, Delpo, Delpo!'' rang down from Arthur Ashe Stadium as Wawrinka respectfully waited to serve. ''Thank you,'' the chair umpire said, pleading for silence to no avail.
Del Potro squinted hard and bowed his head and finally applauded with his racket. Then the third-seeded Wawrinka closed out a 7-6 (5), 4-6, 6-3, 6-2 victory to reach his second straight U.S. Open semifinal.
''I can lose the match, but I will never forget this,'' del Potro said. ''It's bigger than any match. ... They made me so happy tonight, and I don't mind the score.''
It was 32 days earlier that del Potro played his first match at the Rio Olympics - which he figured would be his last because he drew top-ranked Novak Djokovic. After three left wrist surgeries, del Potro lacked the conditioning - not to mention the two-handed backhand - to compete with the best. Or so he thought.
Del Potro beat Djokovic that night. And sobbed afterward. The wins kept coming, and so did the tears, through a victory over a just-as-exhausted Rafael Nadal to clinch a medal, and then after a grueling four-set loss to Andy Murray in the final.
With little time to rest as he received a hero's welcome back in Argentina, the 142nd-ranked del Potro entered his first U.S. Open since 2013 as a wild card. The adoring crowds willed him to victory in round after round, so appreciative of his efforts to come back from the wrist problems that nearly ended his career.
They couldn't quite do it in a 3-hour, 13-minute quarterfinal that ended at 1:20 a.m. Thursday. Del Potro had defeated Wawrinka in the second round at Wimbledon in the initial hint that the Argentine could contend again. But in the rematch, Wawrinka adjusted his tactics in the third set.
He started standing farther back on del Potro's serves, setting himself up to push his opponent from sideline to sideline in long rallies. Wawrinka needed to save a match point in a five-set third-round match, but now he's in Friday's semifinals against sixth-seeded Kei Nishikori.
''It's not a player that I can really play always the way I want because he's so aggressive,'' Wawrinka said of del Potro. ''It was important to stay tough there. I knew it will be difficult. But I'm happy with the way I was fighting, with myself. I'm happy with the way I find solutions in the third set to take advantage.''
Maybe if del Potro had won the opening set, he could have prevailed in three. He was up a break in the first, but after too many mistakes, he lost in a tiebreaker that left him punching his own head in frustration. It was the first set he'd dropped all tournament.
But mostly there was joy on the court. During that tiebreaker, he argued that Wawrinka challenged a call too late, then wound up playfully rubbing the chair umpire's head.
Del Potro's ranking will skyrocket into the top 65 next week - no more needing wild cards into the majors. He looks forward to an offseason to hone his conditioning so he can hang with a player like Wawrinka in a best-of-five match.
''Now I'm fighting at the same level as the top guys, and I already beat Djokovic, Rafa. I played against Murray in a great match,'' del Potro said. ''Wawrinka is the No. 3 player in the world, and I'm there. That means something good to me.
''But I need to keep working.''